The effect of thermal water aeration and water—rock interaction

This paper aims at determining the behavior of thermal water brought to surface and how this might impact reinjection wells and the rock during reinjection. The biggest problem is that reinjection wells are predisposed to choking. We searched for a method to examine this process, including a model for physico-chemical changes in the water—rock interaction. Two different samples of powdered rock (designated α and β) were analyzed using thermal water samples from production and reinjection wells. The pH shows significant differences between the samples from wells where free water treatment was carried out, and those from the aerated thermal waters, as well as for the rock sample. Basically, a decrease in sediment volume can be obtained by increasing the pH. The salt effect was more coherent. Its result was an interesting case of W-shaped graphs from the producing well. On the other hand there is virtually no difference between the samples with acid titration

A Cross-Sectional Survey on Professionals to Assess Health Needs of Newly Arrived Migrants in Spain

Atención sanitaria; Migrante; EncuestaAtenció sanitària; Migrant; EnquestaHealthcare; Migrant; SurveyHeightened conflicts and lack of safety due to reasons related to economic, social, ethnic, religious, sexual orientation, political, or nationality matters have increased migratory movements during the last, few decades. Unfortunately, when migrants arrive in new territories, they can face many barriers. For example, in Spain, some migrants have difficulties in accessing health services. The main objective of this study was to describe, from the perspective of social and healthcare professionals, health needs and barriers faced among migrants who recently arrived in Spain when accessing the health system. To accomplish this aim, we carried out a cross-sectional descriptive study using a newly created self-administered questionnaire. Statistical analysis was done using the SPSS 23.00® program. Survey collection was from April 2018 to October 2018, and the cohort comprised a total of 228 professionals. Most participants were females (76%), with an average age of 35 years [interquartile range (IQR) 29.8–43.0]. The most represented profession in the cohort was physician (48%), followed by social care professionals (32%), nursing (11%), and other (8%). Of these individuals, 61% stated having either little or limited knowledge of international migrant health rights, and 94% believed migrants must overcome barriers to receive health services. The four most reported barriers were as follows: language, cultural differences, administrative issues, and fear of being undocumented. Additionally, by order of importance, professionals viewed mental health disorders and infectious diseases as the most common contributors to disease burden in this group. The four most popular strategies implemented by professionals to improve healthcare access further for migrants included intercultural competency training for professionals; access to community health agents; access to translators; and development of health system navigation skills among those newly arrived. Study results suggest that governments should make greater efforts to provide social and healthcare professionals with more effective tools that overcome communication barriers and cultural competence training modules.Research reported in this publication was supported by co-funding from the Third EU Health Program (2014-2020) Project Grants (HP-PJ-2016) under Grant Agreement 738091 (MyHealth Consortium)

Amorphous and Polycrystalline Photoconductors for Direct Conversion Flat Panel X-Ray Image Sensors

In the last ten to fifteen years there has been much research in using amorphous and polycrystalline semiconductors as x-ray photoconductors in various x-ray image sensor applications, most notably in flat panel x-ray imagers (FPXIs). We first outline the essential requirements for an ideal large area photoconductor for use in a FPXI, and discuss how some of the current amorphous and polycrystalline semiconductors fulfill these requirements. At present, only stabilized amorphous selenium (doped and alloyed a-Se) has been commercialized, and FPXIs based on a-Se are particularly suitable for mammography, operating at the ideal limit of high detective quantum efficiency (DQE). Further, these FPXIs can also be used in real-time, and have already been used in such applications as tomosynthesis. We discuss some of the important attributes of amorphous and polycrystalline x-ray photoconductors such as their large area deposition ability, charge collection efficiency, x-ray sensitivity, DQE, modulation transfer function (MTF) and the importance of the dark current. We show the importance of charge trapping in limiting not only the sensitivity but also the resolution of these detectors. Limitations on the maximum acceptable dark current and the corresponding charge collection efficiency jointly impose a practical constraint that many photoconductors fail to satisfy. We discuss the case of a-Se in which the dark current was brought down by three orders of magnitude by the use of special blocking layers to satisfy the dark current constraint. There are also a number of polycrystalline photoconductors, HgI2 and PbO being good examples, that show potential for commercialization in the same way that multilayer stabilized a-Se x-ray photoconductors were developed for commercial applications. We highlight the unique nature of avalanche multiplication in a-Se and how it has led to the development of the commercial HARP video-tube. An all solid state version of the HARP has been recently demonstrated with excellent avalanche gains; the latter is expected to lead to a number of novel imaging device applications that would be quantum noise limited. While passive pixel sensors use one TFT (thin film transistor) as a switch at the pixel, active pixel sensors (APSs) have two or more transistors and provide gain at the pixel level. The advantages of APS based x-ray imagers are also discussed with examples

Activation of P-P bonds in unsymmetrically substituted diphosphenes

Seit langem werden zweizähnige Liganden in der metallorganischen Chemie, der Koordinationschemie und der Katalyse angewendet. Für die Synthese solcher Liganden haben in neuerer Zeit Additionen an Alkene an Beachtung gewonnen, bei denen simultan zwei Donorgruppen in ein organisches Gerüst eingeführt werden. Mögliche Syntheserouten zu P,P-Donorliganden, die ebenfalls große Bedeutung haben, wurden in der doppelten Substitution 1,2-disubstituierter Olefine oder der Addition der P,P-Bindungen von Diphosphanen an Alkene oder Alkine gefunden. Unsere Gruppe hat unlängst N-heterocyclische Phosphane beschrieben, die sich durch außerordentlich reaktive P-P-Bindungen auszeichnen und mit Alkenen und Alkinen unter Phosphanylphosphanierung zu Hybrid-Bisphosphanen reagieren, die zwei Donorzentren mit unterschiedlichen elektronischen Eigenschaften aufweisen. Verbindungen dieses Typs stoßen auf reges Interesse als Liganden in der Katalyse. Ein Ziel dieser Doktorarbeit soll die Herstellung neuartiger N-heterocyclischer Diphosphane mit reaktiver P-P-Bindung sein, die anstelle eines Diazaphospholenrings aus acyclischen oder auch benzannellierten P-substituierten Diazaphospholen-Derivaten aufgebaut sind. Ziel ist hierbei, weitere Derivate mit polaren und damit reaktiven P-P-Bindungen aufzubauen, deren Donorzentren unterschiedliche stereochemische Eigenschaften haben. Ob die neuartigen Diphosphane P-P-Bindungspolarisation aufweisen und in Folge dessen eine reaktive P-P-Bindungen besitzen, wird am einfachsten durch Untersuchung des P-P-Abstands nachgewiesen. Deswegen ist es nötig, experimentelle Bestimmungen von P-P-Abständen dieser Verbindungen durch Röntgenstrukturuntersuchungen vorzunehmen, weshalb der Erhalt einkristalliner Proben der Zielverbindungen von entscheidender Bedeutung ist. Die Reaktivität der hergestellten Diphosphane gegenüber Alkenen und Alkinen soll untersucht werden. Die erhaltenen 1,2-Bisphosphane sollen in Bezug auf ihre Koordinationseigenschaften weiterhin eingehender durch die Herstellung von Metall-Komplexen untersucht werden. Hierbei wurde festgestellt, dass die Addition der P-P-Bindung an mono- oder disubstituierte Alkine regio- und Z-stereospezifisch unter Bildung eines einzigen Additionsprodukts abläuft. 1,2-Additionsreaktionen des Diphosphans an Fumarsäure-dimethylester beziehungsweise Maleinsäure-diethylester verliefen nicht stereospezifisch, sondern es wurden verschiedene Produkte erhalten. Eine cis-stereospezifische 1,2-Additionsreaktion war dagegen bei der Reaktion des Diphosphans mit Maleimid zu beobachten. Dies kann auf die starre Ringstruktur des Maleimids zurückgeführt werden. Von allen diesen Produkten wurden Komplexe erhalten.Bidentate ligands are widely used in organometallic and coordination chemistry as well as in catalysis. As a rational way to their synthesis, additions to alkenes or alkynes that allow simultaneous introduction of two donors to an organic backbone have recently attracted attention. Analogous approaches to P,P-donor ligands, which are likewise of great significance, can be accessed via double metathesis of activated 1,2-disubstituted olefins, or via addition of the P-P bond of diphosphene to alkene or alkyne. As we had demonstrated some time ago, the more reactive N-heterocyclic phosphine may undergo similar addition reactions to activated alkenes or alkynes to give 1,2-bisphosphines featuring two donor sites with different electronic properties on a saturated and unsaturated C2-backbone. Hybrid chelating ligands of this type have received interest as ligands for specific applications in catalysis. We have now investigated whether a similar chemical behaviour can also be established for other types of diphosphines. For this purpose we have synthesised and characterised benzannulated P-phosphanyl-diazabenzophospholenes and acyclic 1,1-Diamino-diphosphines. A goal is here to develop further derivatives with polar and reactive P-P bond with an electronically different donor centre. The easiest method to establish whether the P-P bond of the new diphosphine exhibits polarity and whether there is reactivity toward to alkynes and alkenes, is to investigate the P-P bond length. Therefore it is necessary to experimentally measure the P-P distances of these compounds by single crystal X-ray diffraction studies. Acquiring single-crystal samples of the target compounds is hence of utmost importance. The reactivity of the new diphosphines towards electron deficient alkynes and alkenes was to be studied, with special emphasis on the regio- and stereoselectivity of the addition step. New 1,2-bisphosphines synthesised in this manner with two sterically and electronically different phosphorus donor centres will be presented. The coordination chemistry of these species was demonstrated by the synthesis of metal complexes. As a result of this work it was found that the addition of unsymmetrical diphosphines to mono- or di-substituted electron poor alkynes is regioselective and Z-stereospecific and generates only one addition product. The addition to maleic or fumaric diesters is not stereospecific but yields a mixture of dl- and meso-isomers. In contrast, the cis-stereochemistry of the double bond is conserved during the addition of diphosphine to maleic imide, presumably as a consequence of the rigidity induced by the cyclic substrate structure

Laccase-catalyzed domino reactions of catechols and hydroquinones with 1,3-dicarbonyls

In der vorliegenden Arbeit wurden neuartige Dominoreaktionen beschrieben, die auf Laccase-katalysierten Oxidation von Brenzcatechinen und Hydrochinonen zu den entsprechenden o- und p-Chinonen und sich daran anschließenden Umsetzungen mit 1,3-Dicarbonylen beruhen. Im ersten Teil dieser Dissertation wurde ein effizienter Zugang zu 3,4-Dihydro-7,8-dihydroxy-2H-dibenzofuran-1-onen entwickelt, der sich die Laccase-initiierte Dominoreaktion zwischen Cyclohexan-1,3-dionen und Brenzcatechinen mit Luftsauerstoff als Oxidationsmittel Zunutze macht. Die Reaktionen konnten unter milden Reaktionsbedingungen und unter Vermeidung von toxischen Reagenzien durchgeführt werden. Die Produkte entstanden mit Ausbeuten zwischen 70 und 97% und mit hoher Reinheit. Nebenprodukte traten nicht auf. Die Struktur aller Verbindungen wurde zweifelsfrei durch NMR-spektroskopische Methoden aufgeklärt. Im zweiten Teil der Arbeit wurden Laccase-initiierte Reaktionen zwischen Brenzcatechinen und heterocyclischen 1,3-Dicarbonylen (Pyridinone, Chinolinone, Thiocumarin) beschrieben, bei denen Benzofuropyridinone, Benzofurochinolinone und Thiocoumestane entstanden. Die Umsetzungen lassen sich einfach durchführen und liefern die Produkte regioselektiv und mit Ausbeuten zwischen 55 und 98%. Mit Barbitursäurederivaten beobachtete man ausschließlich die Bildung von Dispiropyrimidinonen. Die eindeutige und vollständige Strukturaufklärung aller Reaktionsprodukte gelang mittels NMR-spektroskopischer Methoden (HSQMBC und Band-selektives HMBC), sowie durch Röntgenstrukturanalyse. Im dritten Teil der Arbeit wurden die Laccase-katalysierten Reaktionen von unterschiedlich substituierten Hydrochinonen mit cyclischen 1,3-Dicarbonylen untersucht. Die Reaktionen bieten einen hochselektiven Zugang zu Bisaddukten, bei denen die beiden 1,3-Dicarbonyl-Substituenten immer benachbart angeordnet sind. Eine Ausnahme ist die Umsetzung von Chlorhydrochinon mit 4-Hydroxy-cumarin, da hier ein Trisaddukt entsteht. Dieses Ergebnis ist vor allem deshalb bemerkenswert, weil bei der Umsetzung von Hydrochinonen mit 1,3-Dicarbonylen unter anderen Reaktionsbedingungen in der Regel die Bildung von Benzofuranderivaten beobachtet wurde. Die Strukturaufklärung wurde durch NMR-spektroskopische Methoden, wie die Spin-Muster Analyse der long-range gekoppelten C=O-Kohlenstoffatome und die 13C-Satelliten-Analyse in den 1H-NMR-Spektren durchgeführt. Mit den hier entwickelten Dominoreaktionen gelingt die effiziente und selektive Darstellung einer ganzen Reihe von Heterocyclen sowie von substituierten p-Benzochinonen unter milden Reaktionsbedingungen. In den meisten Fällen lassen sich die Produkte in guten bis sehr guten Ausbeuten und mit hoher Reinheit isolieren. Für die Strukturaufklärung der Produkte wurde u. a. eine ganze Palette von NMR-Methoden herangezogen.In the present work novel domino reactions have been described which are based on the laccase-catalyzed oxidation of catechols and hydroquinones to the corresponding o- and p-quinones and their subsequent reactions with 1,3-dicarbonyl compounds. In the first part of this thesis an efficient approach to 3,4-dihydro-7,8-dihydroxy-2H-dibenzofuran-1-ones has been developed. The method includes a laccase-initiated domino reaction between cyclohexane-1,3-diones and catechols using air as an oxidant. The reactions can be carried out under mild reaction conditions without using toxic reagents. The products were obtained in yields ranging from 70 to 97% and with high purity. Byproducts were not formed. The structures of all products were unambiguously elucidated by NMR spectroscopic methods. In the second part of this work laccase-initiated domino reactions between catechols and heterocyclic 1,3-dicarbonyls have been presented. Using pyridinones, quinolinones and thiocoumarin as substrates, the corresponding benzofuropyridinones, benzofuroquinolinones and thiocoumestans were being obtained. The reactions could be easily performed to deliver the products regioselctively in yields ranging between 55 and 98%. In contrast, polycyclic dispiropyrimidinones were exclusively formed when barbituric acid derivatives were employed as substrates. The unambiguous and complete structure elucidation of all products has been achieved by NMR spectroscopic methods (HSQMBC and band-selective HMBC) as well as by X-ray crystal structure analysis. In the third part of this work laccase-catalyzed transformations between differently substituted hydroquinones and 1,3-dicarbonyls have been studied. These reactions provide a new and highly selective method for the formation of quinone bisadducts with two adjacent 1,3-dicarbonyl substituents. The only exception is the reaction of 2-chlorohydroquinone with 4-hydroxycoumarin which delivers a trisadduct. It is noteworthy that under different conditions the reaction between hydroquinones and 1,3-dicarbonyls resulted in the formation of benzofuran derivatives. The unambiguous structure elucidation of all products has been achieved by NMR spectroscopic methods including spin pattern analysis of the long-range coupled C=O carbons and 13C satellites analysis in 1H NMR spectra. The domino reactions presented in this thesis allow for the efficient and selective synthesis of numerous heterocyclic systems as well as substituted p-benzoquinones under mild reaction conditions. In most cases the products can be isolated in good to very good yields and with high purity. For the structure elucidation of the products a wide range of NMR methods was used

Perfluoro-p-xylene as a new unique monomer for highly stable arylene main-chain ionomers applicable to low-t and high-t fuel cell membranes

In this study, we present the synthesis and the characterization of novel functionalized arylene main-chain ionomers based on perfluoro-p-xylene (PFX). The polymers were prepared by polycondensation of PFX and 4,4'-dihydroxybiphenyl or bisphenol 2,2-bis(4-hydroxyphenyl)-hexafluoropropane (bisphenol AF). After polymerization, the PFX unit was still able to undergo nucleophilic aromatic substitution reaction, which was used to introduce phosphonic acid groups into the polymer via a reaction with tris(trimethylsilyl)phosphite. Furthermore, electrophilic sulfonation of these polymers was possible in the bisphenol unit when using H2SO4/SO3 as the sulfonation agent. The so-obtained water-soluble PFX-based polyelectrolytes showed excellent chemical stability and were blended with polybenzimidazoles. The blend membranes formed flexible and mechanically robust films with excellent chemical and thermal stabilitie